新型4自由度并联机构的运动学建模与分析

Kinematics Modeling and Analysis of a 4-DOF Parallel Mechanism

基于并联机器人机构的运动输出理论,考虑结构的对称性和支链的可重组性,构造出一种新型的具有三平移一转动的4自由度并联机器人机构。运用Denavit-Hartenberg表示方法建立机构位移反解模型并进行了数值验算。通过分析反解模型,找出影响机构可达工作空间的因素。引入蒙特卡罗方法思想,提出一种定姿态三维网格搜索方法来得到工作空间,利用Matlab软件编程,以图解形式描绘定姿态下的工作空间容积及工作空间与姿态角的变化态势,并对其进行了分析。

The original design of a 4-DOF parallel platform, and kinematics problems of the position inverse modeling and the workspace analysis are studied. First, considering in symmetry of parallel kinematic structures and re-configurable of kinematic limbs a novel 4-DOF parallel robot mechanism for realizing three-dimension translations and one rotation is put forward according to the output motion theories of parallel mechanism. Second, its positional inverse modals are set up by means of the Denavit-Hartenberg notation then numerical methods are applied to verify them. Third, through analysis of the inverse modals the factors affecting the reachable workspace of the mechanism are found out. From the point of view of Monte Carlo a standing pose and 3-D mesh scanning procedure is presented to get the workspace, then by programming with Matlab the workspace volume of standing pose and variations between the workspace volume and pose angles are traced and analyzed. The results are used as bases of optimal design and trial of physical mechanism of the parallel platform.